Allows users of the Low Level REST client to specify which hosts a
request should be run on. They implement the `NodeSelector` interface
or reuse a built in selector like `NOT_MASTER_ONLY` to chose which nodes
are valid. Using it looks like:
```
Request request = new Request("POST", "/foo/_search");
RequestOptions options = request.getOptions().toBuilder();
options.setNodeSelector(NodeSelector.NOT_MASTER_ONLY);
request.setOptions(options);
...
```
This introduces a new `Node` object which contains a `HttpHost` and the
metadata about the host. At this point that metadata is just `version`
and `roles` but I plan to add node attributes in a followup. The
canonical way to **get** this metadata is to use the `Sniffer` to pull
the information from the Elasticsearch cluster.
I've marked this as "breaking-java" because it breaks custom
implementations of `HostsSniffer` by renaming the interface to
`NodesSniffer` and by changing it from returning a `List<HttpHost>` to a
`List<Node>`. It *shouldn't* break anyone else though.
Because we expect to find it useful, this also implements `host_selector`
support to `do` statements in the yaml tests. Using it looks a little
like:
```
---
"example test":
- skip:
features: host_selector
- do:
host_selector:
version: " - 7.0.0" # same syntax as skip
apiname:
something: true
```
The `do` section parses the `version` string into a host selector that
uses the same version comparison logic as the `skip` section. When the
`do` section is executed it passed the off to the `RestClient`, using
the `ElasticsearchHostsSniffer` to sniff the required metadata.
The idea is to use this in mixed version tests to target a specific
version of Elasticsearch so we can be sure about the deprecation
logging though we don't currently have any examples that need it. We do,
however, have at least one open pull request that requires something
like this to properly test it.
Closes#21888
The current "Building Queries" and "Building Aggregations" pages are
located under the "Supported Apis" section because they are linked to
the "Search API" page.
It should instead be in a dedicated section: this commit adds a new
"Using Java Builders" section and renames few filenames in favor of
more meaningful names.
Nik Everett
David Pilato
Tanguy Leroux